Internal combustion engines generate mechanical energy by burning a mixture of fuel and a source of oxygen, the oxygen generally obtained by the intake of ambient air. In a diesel engine, the combustion process involves burning a mixture of diesel fuel and air, which results in the generation of exhaust, which includes exhaust gases and particulate matter. The particulate matter is often referred to as soot. The exhaust, including the particulate matter, is exhausted from the diesel engine through an exhaust system. A diesel particulate filter (DPF) is often employed as part of the exhaust system in order to filter all or most of the soot from the exhaust before the exhaust is released from the exhaust system.
Over time, particulate matter trapped by the filter can accumulate in the filter and reduce the operating efficiency of the associated engine. Specifically, a substantially clogged filter can increase the back pressure to the engine and hinder the ability of the engine to discharge waste exhaust gases. As a result, the engine must consume more fuel and work harder to produce the same amount of power as compared to when the filter is free of accumulated particulates. Accordingly, exhaust regeneration systems are often employed to periodically clean the filter. Such regeneration systems generally free the filter of particulates by heating the particulates to temperatures sufficient to combust or vaporize the particulates.
Exhaust regeneration systems may use any one of a variety of different ways to determine if such cleaning of the filter is necessary. One method involves monitoring the pressure differential across the filter to determine if the back pressure indicates excessive soot loading. More specifically, the pressure differential is typically measured using pressure sensors that are coupled to each of the upstream and downstream conduits, located before and after the particulate filter, through relatively narrow tubes which place the pressure sensors in direct fluid communication with exhaust gases entering and exiting the filter. If the back pressure, or the pressure of gases detected within the conduit located upstream of the filter, is significantly greater as compared to that of the downstream conduit, the pressure sensor may produce an electrical signal to an electronic control unit (ECU), or the like, to suggest filter regeneration.
Currently existing systems place the pressure sensors substantially in direct line with the exhaust gases passing through the particulate filter. Although fairly accurate, such exposure allows soot, water, ice, and the like, to build up within and clog the tubes or lines leading to the sensors over time. Excessive build up and clogging of the pressure sensor lines can cause significant errors in pressure readings if not complete mechanical and/or electrical failure of the sensors. Such setbacks can prevent prompt alert for the need to clean or regenerate the filter, which can further result in inefficient engine performance and excess fuel consumption. Similarly, repairs for unclogging the pressure sensor lines or for replacing the pressure sensor assembly can cause additional downtime and costs.
The present disclosure is directed to overcoming one or more of the problems associated with the prior art exhaust regeneration systems identified above.